In recent years, pseudodynamic traffic having a large size has increased, such as an increase in communication via a data center accompanied with progress in LTE-A or cloud computing. In order to highly efficiently accommodate such traffic, integrated accommodation of sub-λ (electrical) path and wavelength path is required.
More specifically, in order to improve the accommodation efficiency of traffic (e.g., sub-λ paths or electrical paths which are communication paths that can be electrically processed) in a wavelength path, grooming (to bundle a plurality of paths or traffic elements) should be performed at a relay node and the node at which the grooming is performed needs to be changed depending on the amount of traffic. In this process, wavelength continuity constraint, in which a single wavelength needs to be allocated to a range from a start node to a relay node or an end node, must be considered.
A known method of grooming sub-λ paths by means of a multi-hop logical route has been proposed so as to reduce traffic blocking (see, for example, Non-Patent Document 1).
In a fixed-order multi-hop (FOMH) grooming algorithm disclosed in Non-Patent Document 1, the number of logical hops is not considered. Additionally, when a physical route is designed, it is important to produce a balanced route in consideration of the use state of wavelengths so as to reduce the need for further extension of traffic.
In addition, as a method of designing redundant routes utilized to implement a highly reliable network, a k-vertex-disjoint algorithm to compute k path routes (k is a natural number) having no node overlapping is known (see, for example, Non-Patent Document 2).
Furthermore, as an algorithm utilized to prevent any link having pipeline overlapping, a shared risk link group (SRLG) disjoint path algorithm is known (see, for example, Non-Patent Document 3).
Additionally, in each sub-network produced by dividing a network into sub-networks, the start points or the end points of redundant routes may not coincide with each other. A two sources, two destinations-fixed source/destination pairs algorithm is known (see, for example, Non-Patent Document 4).
However, when redundant routes in a sub-network (NW) produced by dividing a network into sub-networks are designed utilizing any conventional redundant route design method, it is impossible to avoid both pipeline overlapping and overlapping of nodes and links as much as possible. In addition, for a multilayer including sub-λ and wavelength paths, no method of designing highly reliable redundant routes having a high accommodation efficiency is known.